Symptoms and Signs of Tetralogy of Fallot

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 8/6/2021

Doctor's Notes on Tetralogy of Fallot

Tetralogy of Fallot is a common congenital (present at birth) heart defect in children. The defects cause oxygen-poor blood to be pumped out of the heart and into the circulatory system of the body due to a ventricular septal defect (VSD). The organs and tissues of the body need more oxygen than is provided by the blood leaving the heart organs which results in a condition called hypoxemia (low blood oxygen).

Symptoms of tetralogy of Fallot include cyanosis (skin, lips, and mucous membranes inside the mouth and nose appear as dusky blue color), growth and development are slower, puberty may be delayed if the tetralogy is untreated, the child tires easily and begins panting with any form of exertion, and once able to walk, the child often assumes a squatting position to catch his or her breath before resuming physical activity. Episodes of extreme blue coloring (hypercyanosis or "tet spells") can occur, usually in the first 2-3 years of life. Symptoms of hypercyanosis include the child suddenly turning blue, having difficulty breathing, and becoming extremely irritable or faint.

What Is the Treatment for Tetralogy of Fallot?

Tetralogy of Fallot is treated with surgery, however, corrective surgery does not cure the condition.

At age 3-6 months, surgery is done to close the ventricular septal defect (VSD) and relieve the narrowing between the right ventricle and the pulmonary artery that causes the low oxygen levels.

  • With treatment, the 30-year survival ranges from 68.5% to 90.5%

If tetralogy of Fallot is not treated surgically early on in life, a child may not develop properly due to low oxygen levels. Complications of tetralogy of Fallot include:

  • Increased risk of bacterial infection of the inner lining of the heart or heart valve (infective endocarditis)
  • Untreated cases may result in disability by adulthood, or even death

Complications of corrective surgery for tetralogy of Fallot include:

  • Bleeding
  • Compression of the heart due to fluid buildup (tamponade)
  • Persistent elevation in right ventricular (RV) pressures
  • Right-sided heart failure
  • Chest wound infection
  • Pulmonary valve insufficiency
  • Persistent RV outflow tract obstruction
  • Atrial and ventricular arrhythmias


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.